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Optical Coherence Tomography (Oct) and Fundus Fluorescein Angiography (FFA) in Neuro-Ophthalmology
Published in Vivek Lal, A Clinical Approach to Neuro-Ophthalmic Disorders, 2023
Ramandeep Singh, Deeksha Katoch, Mohit Dogra, Basavaraj Tigari, Simar Rajan Singh, Sahil Jain, Bruttendu Moharana, Sabia Handa, Mangat R. Dogra
In the acute phase of nonarteritic-anterior ischemic neuropathy (NA-AION), the pRNFL loss cannot be predicted. However, it is known in primate eyes that degree of initial pRNFL swelling correlated with the severity of atrophy as well as functional impairment as seen on electrophysiological responses.28 In early phase, mRGC thinning correlated more with visual field loss.29 Further, it has been shown that macular ganglion cell inner plexiform layer (GCIPL) thinning is significant in AION eyes as compared to unaffected eye.30
Biochemical Markers in Ophthalmology
Published in Ching-Yu Cheng, Tien Yin Wong, Ophthalmic Epidemiology, 2022
Abdus Samad Ansari, Pirro G. Hysi
Disease-associated genes often share basic functional properties, whose study can inform about disease mechanisms. There are many functional gene sets that are statistically enriched among the GWAS-identified POAG genes. One very enriched set of functional properties among POAG-associated genes is the cell cycle, cell division, inhibition, and apoptosis [53, 63]. These genes tend to be associated with endophenotypes underlying optic disc morphology features, such as VCDR, disc and rim areas. This seems to suggest that retinal ganglion cell vitality may be a mechanism leading to glaucoma. The presence of such a strong link between cell division inhibition and POAG points to potentially new and transformative pharmacological POAG treatments that will aim to boost cells’ regenerative capabilities and resilience. This is interesting, as to date there is only one available therapeutical option with neuroprotective properties (brimonidine). Experimental intervention aimed at inhibiting cyclin-dependent kinases, a protein family, which also included the CDKN2B protein, whose production and activity are under strong genetic regulation in POAG, have shown neuroprotection and improved clinical outcomes [64, 65]. Extending these studies to human glaucoma patients may lead to the development of novel treatments against the disease.
Comparative Anatomy and Physiology of the Mammalian Eye
Published in David W. Hobson, Dermal and Ocular Toxicology, 2020
The inner plexiform layer is formed by the axons of the bipolar and amacrine cells and the dendrites of the ganglion cells.4 The ganglion cells form a single layer over most of the retina, the exception being adjacent to the fovea in those species in which this is present. The axons of the ganglion cells are aggregated into nerve fiber bundles which make up the nerve fiber layer. These bundles travel parallel to the retinal surface through arcades formed by the foot processes of the Muller cells.4 These are nonmyelinated nerve fibers until they reach the optic nerve where they acquire myelination. Depending on the species and where the myelination begins, it may be evident clinically. The innermost layer of the retina is the internal limiting membrane. This is a thick basement membrane that is smooth on its internal surface, but conforms to the uneven Muller cell basal plasma membrane externally.4
Mimicking chronic glaucoma over 6 months with a single intracameral injection of dexamethasone/fibronectin-loaded PLGA microspheres
Published in Drug Delivery, 2022
Alba Aragón-Navas, María J. Rodrigo, David Garcia-Herranz, Teresa Martinez, Manuel Subias, Silvia Mendez, Jesús Ruberte, Judit Pampalona, Irene Bravo-Osuna, Julian Garcia-Feijoo, Luis E. Pablo, Elena Garcia-Martin, Rocío Herrero-Vanrell
Animals were euthanized under humanity conditions with an intracardiac injection of sodium thiopental (25 mg/ml) under general anesthesia and eyes were immediately enucleated. Paraffin-embedded eyes were sectioned (5 µm) along the eye axis, deparaffinized and rehydrated. After several washes in phosphate-buffered saline (PBS), sections were incubated overnight at 4 °C with mouse anti-Brn3a (Santa Cruz Biotechnology, Heidelberg, Germany) at 1:50 dilution. After washing the sections in PBS, slides were incubated for 2 hours at room temperature with biotinylated horse anti-mouse at 1:50 dilution (Vector Laboratories, Burlingame, CA, USA). Then, incubation with ABC-HRP (Thermo Fisher Scientific, Waltham Massachusetts, USA) at 1:50 dilution at room temperature was performed. Finally, sections were stained with DAB (Sigma-Aldrich) for 3 minutes and counterstained with Harrys Hematoxylin (Sigma-Aldrich) for 20 minutes at room temperature. Ganglion cells were counted in radial sections of the retina, along 2 mm of a linear region of the ganglion cell layer, at four areas, two in both sides of the optic nerve head. Images were analyzed by an operator blinded to treatment groups. Statistical analysis of the number of ganglion cells was conducted in R (v. 3.6.0) using a paired t-test. The results are shown as mean ± SEM. Values of p < 0.05 were considered statistically significant. Procedural immunohistochemistry controls were carried out by omitting the primary antibody in a sequential tissue section.
microRNA-26a-5p Prevents Retinal Neuronal Cell Death in Diabetic Mice by Targeting PTEN
Published in Current Eye Research, 2022
Rui Shi, Dan-Dan Liu, Ying Cao, Yu-Shun Xue
Retinal ganglion cells are retinal neurons that are affected by many ocular neurodegenerative diseases. We then used TEM to observe the ultrastructure of the retinal ganglion cells to further identify the early pathological changes of the retina. These results reveal that the number and size of mitochondria were significantly decreased in the ganglions of diabetic mice receiving mimic control injection (Figure 4c and d) compared with the healthy controls (Figure 4a and b), although the morphology of ganglion cells appeared normal. Margination of chromatin and crenated nuclei of cells in the ganglion cell layer was also detected in the retina of diabetic mice. However, in mice injected with miR-26a, the mitochondria, chromatin, and nuclei structures were ameliorated (Figure 4e and f).
The Correlation of Inflammation and Microvascular Changes with Diabetic Retinal Neurodegeneration
Published in Current Eye Research, 2021
Tuna Celik Buyuktepe, Sibel Demirel, Figen Batıoğlu, Emin Özmert
All SD-OCT image sets contained a minimum of 13 B-scans distributed in a horizontal raster pattern, with a scan speed of 27,000 A-scans/second, a scan depth of 2.00 mm, axial resolution of 5 µm, and transverse resolution of 15 µm. After pupillary dilation, each subject was seated in front of the OCT scanner, and their head was stabilized on the chin rest. An internal fixation target was used to avoid eye movement. Retinal layers and thickness analysis were recorded in the foveal area (1-mm zone centered on the fovea as defined by the Early Treatment Diabetic Retinopathy Study, ETDRS). The automatic segmentation of the retinal layers was performed, and the segmentation lines were manually adjusted if needed. The thicknesses of the following layers were recorded: 1) the retinal nerve fiber layer (RNFL), 2) the ganglion cell layer (GCL), 3) the inner plexiform layer (IPL), 4) the inner nuclear layer (INL), 5) the outer plexiform layer (OPL), 6) the outer nuclear layer (ONL), and 7) the retinal pigment epithelium (RPE). The total retinal thickness was defined as the distance between the vitreoretinal interface and the anterior surface of the RPE along each A-scan. The “inner retina” was defined as the space lying between the inner aspect of the internal limiting membrane and the inner border of the OPL, whereas the “outer retina” was defined as the space lying between the inner border of the OPL and the inner aspect of the RPE.